In ancient rocks, scientists see a climate cycle working across deep time

(The Earth Institute at Columbia University) Scientists drilling deep into ancient rocks in the Arizona desert say they have documented a gradual shift in Earth's orbit that repeats regularly every 405,000 years, playing a role in natural climate swings. Astrophysicists have long hypothesized that the cycle exists, but the authors of the new research have found the first verifiable physical evidence. They showed that the cycle has been stable for hundreds of millions of years, from before the rise of dinosaurs, and is still active today.